Lighting Question - ERR into MTH F-3

That board picks up the relay coil activation of the PS-1 bottom board and activates the circuit to energize the headlight.  This gives you the directional function.  It is probably a 6V bulb.

I would get a 16-18V bulb and wire directly to the ERR board.  Otherwise you are mixing an AC signal with DC circuit.   G

The Cruise Commander puts out lighting signals that are negative in respect to frame ground.  This complicates the issue for many lighting upgrades.

I suspect George's solution is the easiest, though if I'm putting in a new headlight, I prefer LED's for better light.  I don't know that specific board, so I can't say if it could be cobbled up to make the lighting work, but the separate light connection seems the path of least resistance.

Thanks for the replies, guys.  We'll go with a separate LED headlight.